Method and Apparatus for Accessing Service Resource Items That are For Use in a Telecommunications System

ABSTRACT

Service resource items for use in call setup in a telephone system are held on servers that are connected to a computer network which is logically distinct from the telephone system infrastructure; this computer network may, for example, make use of the Internet. Each service item is locatable on the network at a corresponding URI and is associated with a particular telephone number. A mapping is provided between telephone numbers and the URIs of associated service resource items. When it is desired to access a service resource item associated with a particular telephone number, this mapping is used to retrieve the corresponding URI which is then used to access the desired service resource item.

FIELD OF THE INVENTION

The present invention relates to a method of accessing service resourceitems that are intended to be used in setting up bearer channels througha switched telecommunications system.

As used herein, the term “switched telecommunication system” means asystem comprising a bearer network with switches for setting up a bearerchannel through the network. The term “switched telecommunicationsystem” is to be taken to include not only the existing public andprivate telephone systems (whether using analogue phones or ISDN-based),but also broadband (ATM) and other switch-based bearer networks that arecurrently being implemented or may emerge in the future. Forconvenience, the term “switched telecommunication system” is sometimesshortened herein to telecommunication system.

Reference to a “call” in the context of a switched telecommunicationsystem is to be understood as meaning a communication through a bearerchannel set up across the bearer network, whilst references to callsetup, maintenance and takedown are to be taken to mean the processes ofsetting up, maintaining and taking down a bearer channel through thebearer network. Terms such as “call processing” and “call handling” areto be similarly interpreted.

The term “communication system” when used herein should be understood ashaving a broader meaning than switched telecommunication system, and isintended to include datagram-based communication systems where each datapacket is independently routed through a bearer network withoutfollowing a predetermined bearer channel.

BACKGROUND OF THE INVENTION

Telecommunication companies running PSTNs (Public Switched TelephoneNetworks) and PLMNs (Public Land Mobile Networks) are in the business ofproviding communication services and in doing so are providingincreasing built-in intelligence in the form of “IN services” such as800 number services and call forwarding. In contrast, the World Wide Web(WWW), which has seen explosive growth in recent times, is an example ofan Internet-based global network providing complex information services.These two worlds, that of the large communications utilities and that ofthe highly dynamic, pioneer-spirit WWW information culture, are uneasycompanions and each plans to encroach on the domain previously occupiedby the others; thus telephony services will be offered over the WWW andinformation services over the public communication infrastructure.

The present invention proposes technologies for a more synergeticrelationship between these two worlds than is currently envisaged and inorder to place the present invention in context, a review will first begiven of each of these two worlds.

Telephone Networks with IN Services

The Basic PSTN. The basic service provided by a PSTN (Public SwitchedTelephone Network) is the interconnection of two telephones (that is,setting up a bearer channel between the telephones) according to acalled-party telephone number input at the calling-party telephone. FIG.1 is a simplified representation of a PSTN providing such a service. Inparticular, customer premises equipment, CPE, 10 (such as standardanalogue telephones, but also more recently ISDN terminals) areconnected through an access network 11 to switching points, SPs 12. TheSPs 12 form nodes in an inter-exchange network 13 made up ofinterconnecting trunks 14 and SPs that are controlled by controlentities 15 in the SPs. The control effected by the control entities 15is determined by signaling inputs received from the CPEs and other SPs,and involves call setup, maintenance and clearance to provide thedesired bearer channel between calling CPE and called CPE. Conceptually,the PSTN may be thought of as a bearer network and a control (signaling)network, the function of the latter being to effect call control throughthe bearer network, namely the control of setup, maintenance and takedown of bearer channels through the bearer network; in practice, thebearer and signaling networks may use the same physical circuits andeven the same logical channels.

Thus, where the CPE is a traditional dumb telephone, control signalingbetween the CPE and its local SP is in-band signaling, that is, thesignaling is carried on the same channel as used for voice; thissignaling is interpreted and converted at the SPs 12 into signalingbetween SPs that uses a dedicated common-channel signaling network 16(implemented nowadays using the SS7 protocol suite). Where the CPE is anISDN terminal, signaling is carried in a separate channel directly fromthe CPE on an end-to-end. Modern SPs use the ISUP (ISDN User Part) SS7protocol for inter-exchange call control signaling whether the CPE is astandard telephone or an ISDN terminal.

Telephone Numbering Plans—As certain aspects of the present inventionare influenced by the structuring of telephone numbers, a briefdescription will now be given of the structuring of such numbers.Telephone numbers form an international, hierarchical addressing schemebased on groups of decimal digits. The top level of the hierarchy isadministered by the ITU-T, which has allocated single-digit numericcodes to the major geographic zones (for example “1” for North America,“2” for Africa, “3” for Europe, “4” for Europe, “5” for South Americaand Cuba, etc.). Within each zone countries are assigned 2 or 3 digitcodes, so that within zone 3 France is “33”, and within zone 4 the UK is“44”. Administration of the numbering plan within a country is delegatedto a national body, such as the Office of Telecommunications (“Oftel”)in the UK. The following further description is based on the UKnumbering plan, but the scheme described will be recognised as havingwidespread applicability.

In the UK all national numbers are prefixed by a code from 01 to 09 (the‘0’ prefix is dropped in international dialing). The currently assignedcodes are “01” for Geographic Area Codes, “02” for Additional GeographicArea Codes, “04” for Mobile Services, “07” for Personal Numbers, and“08” for Special Service (freephone, information). Normal wireline PSTNsubscriber telephone numbers are allocated from the Geographic Area Codecodes, and currently only codes prefixed by 01 are allocated. Geographicarea codes are presently 3 or 4 digits (excluding the leading ‘0’) andthere are currently 638 geographic areas each with its own code. A fullnational UK dialed number takes two forms:

0 171 634 8700 area code local number (7 digit) 0 1447 456 987 area codelocal number (6 digit)

The first case has the ‘0’ prefix, a 3 digit area code and a 7 digitlocal number, and the second case has the ‘0’ prefix, a 4 digit areacode, and a 6 digit local number. Further interpretation of the localnumber will take place within the area exchange, as even a 6 digitaddress space is too large for a single switch, and for a typical localarea several switches may be needed to host the required number ofsubscriber lines. This interpretation is opaque and is a matter for thearea service provider.

In the current PSTN the inherently hierarchical and geographicinterpretation of telephone numbers is mirrored by the physicalarchitecture of the network. A telephone number is structured in a waythat makes it easy to route a call through the network. At each step,the prefix of the number provides information about the current routingstep, and the suffix (perhaps opaquely) provides information aboutsubsequent routing steps; as long as a switch knows how to parse aprefix and carry out a routing step, it does not need to understand thecontent of the suffix, which is left for subsequent routing steps. Forthis reason the international and national switching fabric is alsoorganised hierarchically.

Intelligent Networks. Returning now to a consideration of the currenttelephone network infrastructure, in addition to basic call handling, anSP may also serve to provide what are called IN (Intelligent Network)services; in this case the SP is termed a service switching point, SSP.An SSP 25 is arranged to suspend call processing at definedpoints-in-call upon particular criteria being met, and to delegate thecontinuation of call processing to a service control subsystem providinga service control function (SCF) either in the form of a service controlpoint, SCP 17 (see FIG. 2) or an Adjunct 18. The Adjunct 18 is directlyassociated with an SSP 25 whilst the SCP 17 and SSP 25 communicate witheach other via an extended common channel signaling (CCS) network 16that may include signal transfer points (STP) 19. The SCP 17 may beassociated with more than one SSP 25. Both the SCP 17 and Adjunct 18provide a service logic execution environment (SLEE) 20 in whichinstances of one or more service logic programs (SLP) 21 can execute.The SLEE 20 and SLP 21 together provide service control functionalityfor providing services to the SSP 25.

Service logic running in an SCP or Adjunct will generally make use ofsubscriber information stored in a service data function (SDF) 22 thatmay be integral with the SCP/Adjunct or partially or wholly separatetherefrom. The service data function (SDF), like the service controlfunction (SCF) forms part of the service control subsystem of the PSTN.It may be noted that some or all of the service control function may bebuilt into the PSTN switches themselves.

In addition to the SCP 17 and Adjunct 18, the FIG. 2 network includes anintelligent peripheral (IP) 23. The IP 23 provides resources to the SSP25 such as voice announcements and DTMF digit collection capabilities.The network will also include an operation system (not shown) that has ageneral view of the network and its services and performs functions suchas network monitoring and control.

In operation, when the SSP 25 receives a call, it examines internaltrigger conditions and, possibly, user information (eg dialed digits) toas certain if the call requires a service to be provided by the servicecontrol subsystem 17, 18; the checking of trigger conditions may becarried out at several different points in call processing. Where theSSP 25 determines that a service is required it messages the servicecontrol subsystem (either SCP 17 or Adjunct 18) requesting the desiredservice and sending it a logic representation of the call in terms ofits connectivity and call processing status. The service controlsubsystem then provides the requested service and this may involveeither a single interaction between the SSP and service controlsubsystem or a session of interactions. A typical service is callforwarding which is a called-party service giving expression to anend-user requirement as simple as “if you call me on number X and itrings ten times, try calling number Y”. In this case, it is the SSPlocal to the called end-user that triggers its associated SCP (orAdjunct) to provide this service; it will, of course, be appreciatedthat the SSP must be primed to know that the service is to be providedfor a called number X.

The above-described model for the provision of IN services in a PSTN canalso be mapped onto PLMNs (Public Land Mobile Networks) such as GSM andother mobile networks. Control signaling in the case of a mobilesubscriber is more complex because in addition to all the usualsignaling requirements, there is also a need to establish where a callto a mobile subscriber should be routed; however, this is not a verydifferent problem from a number of called-party IN services in the PSTN.Thus in GSM, the service-data function (SDF) is largely located in asystem named a Home Location Register (HLR) and the service controlfunction in a system named a Visitor Location Register (VLR) that isgenerally associated on a one-to-one basis with each SSP (which in GSMterminology is called a Mobile Switching Centre, MSC).

Because subscribers are mobile, the subscriber profile is transportedfrom the HLR to whichever VIR happens to be functionally closest to bemobile subscriber, and from there the VLR operates the (fixed) serviceusing the subscriber profile and interacts with the SSP. The HLR and VLRthus constitute a service control subsystem similar to an SCP or Adjunctwith their associated databases.

It is, of course, also possible to provide IN services in privatetelephone systems and, in this case, the service control function andservice data function are generally either integrated into a PABX(Private Automatic Branch Exchange) or provided by a local computer. Theservice control subsystem, whilst present, may thus not be a physicallydistinct from the PABX.

The above-described general architectural framework for providing INservices has both strengths and flaws. Its main strength is that itworks and many services have been successfully deployed, such as 800number services, credit card calling, voicemail, and various callwaiting and redirection services. However, despite years ofstandardisation, services are still implemented one-at-a-time onproprietary platforms and do not scale well. The approach has been basedon large, fault-tolerant systems which provide services for hundreds ofthousands or even millions of subscribers and take years to deploy.Furthermore, since the networks used to support these services alsoconstitute the basic telephone infrastructure, anything attached tothese networks must be rigorously vetted. Additionally, each country andoperator tends to have local variations of the so-called standardsmaking it difficult to supply standard products and thereby braking thedynamics of competition.

The World Wide Web

In contrast to the slow deliberate progress of the telephoneinfrastructure, the WWW has grown explosively from its inception in 1989to become the primary electronic information distribution service interms of spread, availability and richness of information content.Anyone can, for a modest outlay, become an information provider with aworld-wide audience in a highly interconnected information architecture.

The WWW is a client-server application running over the Internet andusing a client-server protocol which mandates only the simplest ofexchanges between client and server. This protocol is HTTP (Hyper TextTransfer Protocol) which is optimised for use over TCP/IP networks suchas the Internet; the HTTP protocol can, however, also be used overnetworks using different communication protocol stacks.

Since the availability of literature concerning the WWW has seen thesame sort of growth as the WWW itself, a detailed description of theWWW, HTTP and the Internet will not be given herein. An outlinedescription will, however, be given with attention being paid to certainfeatures of relevance to the present invention.

The WWW uses the Internet for interconnectivity. Internet is a systemthat connects together networks on a worldwide basis. Internet is basedon the TCP/IP protocol suite and provides connectivity to networks thatalso use TCP/IP. For an entity to have a presence on the Internet, itneeds both access to a network connected to the Internet and an IPaddress. IP addresses are hierarchically structured. Generally an entitywill be identified at the user level by a name that can be resolved intothe corresponding IP address by the Domain Name System (DNS) of theInternet. Because the DNS or adaptions of it are fundamental to at leastcertain embodiments of the invention described hereinafter, adescription will next be given of the general form and operation of theDNS.

The Domain Name System—The DNS is a global, distributed, database, andwithout its performance, resilience and scalability much of the Internetwould not exist in its current form. The DNS, in response to a clientrequest, serves to associate an Internet host domain name with one ormore Registration Records (RR) of differing types, the most common beingan address (A) record (such as 15.144.8.69) and mail exchanger (MX)records (used to identify a domain host configured to accept electronicmail for a domain). The RRs are distributed across DNS name serversworld-wide, these servers cooperating to provide the domain nametranslation service; no single DNS server contains more than a smallpart of the global database, but each server knows how to locate DNSservers which are “closer” to the data than it is. For present purposes,the main characteristics of the DNS of interest are:

The host name space is organised as a tree-structured hierarchy of nodeswith each host having a corresponding leaf node; each node has a label(except the root node) and each label begins with an alphabeticcharacter and is followed by a sequence of alphabetic characters ordigits. The full, or “fully qualified” name of a host is the string ofnode labels, each separated by a “.”, from the corresponding leaf nodeto the root node of the hierarchy, this latter being represented by aterminating “.” in the name. Thus a host machine “fred” ofHewlett-Packard Laboratories in Bristol, England will have a fullyqualified domain name of “fred.hpl.hp.com.” (note that if a host namedoes not have a terminal “.” it is interpreted relative to the currentnode of the naming hierarchy).

Each host has one or more associated Registration Records (RRs).

There are a plurality of DNS servers each with responsibility for asubtree of the name space. A DNS server will hold RRs for all or part ofits subtree—in the latter case it delegates responsibility for theremainder of the subtree to one or more further DNS servers. A DNSserver knows the address of any server to which it has delegatedresponsibility and also the address of the server which has given it theresponsibility for the subtree it manages. The DNS servers thus point toeach other in a structuring reflecting that of the naming hierarchy.

An application wishing to make use of the DNS does so through anassociated “resolver” that knows the address of at least one DNS server.When a DNS server is asked by this resolver for an RR of a specifiedhost, it will return either the requested RR or the address of a DNSserver closer to the server holding the RR in terms of traversal of thenaming hierarchy. In effect, the hierarchy of the servers is ascendeduntil a server is reached that also has responsibility for the domainnate to be resolved; thereafter, the DNS server hierarchy is descendeddown to the server holding the RR for the domain name to be resolved.

The DNS uses a predetermined message format (in fact, it is the same forquery and response) and uses the IP protocols.

These characteristics of the DNS may be considered as defining a“DNS-type” system always allowing for minor variations such as in labelsyntax, how the labels are combined (ordering, separators), the messageformat details, evolutions of the IP protocols etc.

Due to the hierarchical naming structure, it is possible to delegateresponsibility for administering domains (subtrees) of the name spacerecursively. Thus, the top-level domains are administered by InterNic(these top-level domains include the familiar ‘com’, ‘edu’, ‘org’,‘int’, ‘net’, ‘mil’ domains as well as top-level country domainsspecified by standard two-letter codes such as ‘us’, ‘uk’, ‘fr’ etc.).At the next level, by way of example Hewlett-Packard Company isresponsible for all names ending in ‘hp.com’ and British Universitiesare collectively responsible for all names ending in ‘ac.uk’. Descendingfurther, and again by way of example, administration of the domain‘hpl.hp.com’ is the responsibility of Hewlett-Packard Laboratories andadministration of the subtree (domain) ‘newcastle.ac.uk’ is theresponsibility of the University of Newcastle-upon-Tyne.

FIG. 3 illustrates the progress of an example query made from withinHewlett-Packard Laboratories. The host domain name to be resolved is‘xy.newcastle.ac.uk’, a hypothetical machine at the University ofNewcastle, United Kingdom. The query is presented to the DNS serverresponsible for the “hpl.hp.com” subtree. This server does not hold therequested RR and so responds with the address of the “hp.com” DNSserver; this server is then queried and responds with the address of the‘com’ DNS server which in turn responds with the address of the ‘.’(root) DNS server. The query then proceeds iteratively down the ‘uk’branch until the ‘newcastle.ac.uk’ server responds with the RR recordfor the name ‘xy’ in its subtree.

This looks extremely inefficient, but DNS servers are designed to builda dynamic cache, and are initialised with the addresses of several rootservers, so in practice most of the iterative queries never take place.In this case the ‘hpl.hp.com’ DNS server will know the addresses ofseveral root servers, and will likely have the addresses of ‘uk’ and‘ac.uk’ servers in its cache. The first query to the ‘hpl.hp.com’ serverwill return the address of the ‘ac.uk’ server. The second query to the‘ac.uk’ server will return the address of the ‘newcastle.ac.uk’ server,and the third query will return the RR in question. Any future querieswith a ‘newcastle.ac.uk’ prefix will go direct to the newcastle DNSserver as that address will be retained in the “hpl.hp.com” DNS servercache. In practice names within a local subtree are resolved in a singlequery, and names outside the local subtree are resolved in two or threequeries.

Rather than a resolver being responsible for carrying out the series ofquery iterations required to resolve a domain name, the resolver mayspecify its first query to be recursive in which case the receiving DNSserver is responsible for resolving the query (if it cannot directlyreturn the requested RR, it will itself issue a recursive query to a‘closer’ DNS server, and so on).

It should also be noted that in practice each DNS server will bereplicated, that is, organised as a primary and one or more secondaries.A primary DNS nameserver initialises itself from a database maintainedon a local file system, while a secondary initialises itself bytransferring information from a primary. A subtree will normally haveone primary nameserver and anything up to ten secondaries—the limitationtends to be the time required by the secondaries to update theirdatabases from the primary. The primary database is the master source ofsubtree information and is maintained by the domain DNS administrator.The secondaries are not simply standby secondaries but each activelyparticipates in the DNS with dependent servers that point to it ratherthan to the corresponding primary.

DNS implementations, such as BIND, are widely available as a standardpart of most UNIX systems, and can claim to be among the most robust andwidely used distributed applications in existence.

Operation of the WWW Referring now to FIG. 4 of the accompanyingdrawings, access to the Internet 30 may be by direct connection to anetwork that is itself directly or indirectly connected to the Internet;such an arrangement is represented by terminal 31 in FIG. 4 (thisterminal may, for example, be a Unix workstation or a PC). Having aconnection to the Internet of this form is known as having ‘networkaccess’. Any entity that has network access to the Internet may act as aserver on the Internet provided it has sufficient associatedfunctionality; in FIG. 4, entity 32 with file store 37 acts as a server.

Many users of the WWW do not have network access to the Internet butinstead access the Internet via an Internet service provider, ISP, 33that does have network access. In this case, the user terminal 34 willgenerally communicate with the ISP 33 over the public telephone systemusing a modem and employing either SLIP (Serial Line Interface Protocol)or PPP (Point-to-Point Protocol). These protocols allow Internet packetsto traverse ordinary telephone lines. Access to the Internet of thisform is known as “dialup IP” access. With this access method, the userterminal 34 is temporarily allocated an IP address during each usersession; however, since this IP address may differ between sessions, itis not practical for the entity 34 to act as a server.

A cornerstone of the WWW is its ability to address particularinformation resources by means of an Uniform Resource Identifier (URI)that will generally be either a Uniform Resource Locator (URL) thatidentifies a resource by location, or a Uniform Resource Name (URN) thatcan be resolved into an URL. By way of example, a full or “absolute” URLwill comprise the following elements:

scheme this is the access scheme to be used to access the resource ofinterest; host the Internet host domain name or IP address; port thehost port for the (TCP) connection; abs-path the absolute path of theresource on the host.

In fact, the ‘port’ may be omitted in which case port 80 is assumed.

FIG. 5 of the accompanying drawings shows an example URL for theHewlett-Packard products welcome page. In this case, the elements are:

scheme http host www.hp.com port omitted (port 80 assumed) abs-pathProducts.html

The HTTP protocol is based on a request/response paradigm. Referringagain to FIG. 4 of the drawings, given a particular URI identifying aresource 30 to be accessed, a client establishes a connection with theserver 31 corresponding to the “host” element of the URI and sends arequest to the server. This request includes a request method, and the“Request-URI” (which is generally just the absolute path of the resourceon the server as identified by the “abs-path” element of the URI); therequest may include additional data elements. The server 31 thenaccesses the resource 36 (here held on storage 37) and responds and thisresponse may include an entity of a type identified by a MIME(Multipurpose Internet Mail Extensions) type also included in theresponse.

The two main request methods are:

GET—This method results in the retrieval of whatever information (in theform of an entity) is identified by the Request-URI. It is important tonote that if the Request-URI refers to a data-producing process, it isthe produced data which is returned as the entity in the response andnot the source text of the process.

POST—This method is used to request that the destination server acceptthe entity enclosed in the request as a new subordinate of the resourceidentified by the Request-URI. The POST method can be used forannotation of existing resources, providing a message to a bulletinboard, providing data to a data-handling process (for example, dataproduced as the result of submitting a form), and extending a databasethrough an append operation.

In summary, the GET method can be used to directly retrieve data, or totrigger any process that will return an entity (which may either be dataor a simply an indication of the result of running the process). ThePOST method is used for registering data and specifying this method isalso effective to trigger a process in the server to handle the posteddata appropriately.

The passing of information to a process triggered to run on a serverusing either the GET or POST method is currently done according to aninterface called the Common Gateway Interface (CGI). The receivingprocess is often written in a scripting language though this is notessential. Typically, the triggered server script is used forinterfacing to a database to service a query included in a GET request.Another use, already referred to, is to append data associated with aPOST request to a database.

Other important factors in the success of the WWW is the use of theHyperText Markup Language (HTML) for representing the makeup ofdocuments transferred over the Www, and the availability of powerfulgraphical Web browsers, such as Netscape and Mosaic, for interpretingsuch documents in a client terminal to present them to a user.Basically, HTML is used to identify each part of a document, such as atitle, or a graphic, and it is then up to the browser running in theclient terminal to decide how to display each document part. However,HTML is more than this—it also enables a URI and a request method to beassociated with any element of a document (such as a particular word oran image) so that when a user points to and clicks on that element, theresource identified by the URI is accessed according to the scheme(protocol) and request method specified. This arrangement provides ahyperlink from one document to another. Using such hyperlinks, a user ata client terminal can skip effortlessly from one document downloadedfrom a server on one side of the world, to another document located on aserver on the other side of the world. Since a document created by oneauthor may include a hyperlink to a document created by another, anextremely powerful document cross-referring system results with nocentral bureaucratic control.

Hyperlinks are not the only intelligence that can be built into an HTMLdocument. Another powerful feature is the ability to fill in adownloaded “Form” document on screen and then activate a ‘commit’graphical button in order to have the entered information passed to aresource (such as a database) designed to collect such information. Thisis achieved by associating the POST request method with the ‘commit’button together with the URI of the database resource; activating the‘commit’ button results in the entered information being posted to theidentified resource where it is appropriately handled.

Another powerful possibility is the association of program code(generally scripts to be interpreted) with particular documentselements, such as graphical buttons, this code being executed upon thebutton being activated. This opens up the possibility of usersdownloading program code from a resource and then running the code.

It will be appreciated by persons skilled in the art that HTML is onlyone of several currently available scripting languages delivering thefunctionality outlined above and it may be expected that any serious Webbrowser will have built-in support for multiple scripting languages. Forexample, Netscape 2.0 supports HTML 3.0, Java and LiveScript (the latterbeing Netscape proprietary scripting Language).

The importance of the role of the graphical Web browser itself shouldnot be overlooked. As well as the ability to support multiple scriptinglanguages, a Web browser should provide built-in support for standardmedia types, and the ability to load and execute programs in the client,amongst other features. These browsers may be viewed as operatingsystems for WWW interaction.

WWW and the Telephone Network

It is possible to provide a telephony service over the Internet betweenconnected terminals by digitising voice input and sending it over theInternet in discrete packets for reassembly at the receiving terminal.This is an example of a communication service on the Internet.Conversely, it is possible to point to a variety of information servicesprovided over the telephone system, such as the Minitel system widelyavailable in France. However, these encroachments into each anotherstraditional territories pose no real threat to either the Internet orthe public telephone system.

Of more interest are areas of cooperative use of the Internet and thetelephone system. In fact, one such area has existed for someconsiderable time and has been outlined above with reference to FIG. 4,namely the use of a modem link over the PSTN from a user computer 34 toan Internet service provider 33 in order to obtain dialup IP access tothe Internet. This cooperative use is of a very simple nature, namelythe setting up of a bearer channel over the PSTN for subsequentlygenerated Internet traffic; there is no true interaction between theInternet and the PSTN.

Another known example of the cooperative use of the Internet and PSTN isa recently launched service by which an Internet user with a sound cardin his/her terminal computer can make a voice call to a standardtelephone anywhere in the world. This is achieved by transferringdigitised voice over the Internet to a service provider near thedestination telephone; this service provider then connects into thelocal PSTN to access the desired phone and transfers across into thelocal PSTN the voice traffic received over the Internet. Voice inputfrom the called telephone is handled in the reverse manner. Key to thisservice is the ability to identify the service provider local (intelephony charging terms) to the destination phone. This arrangement,whilst offering the prospect of competition for the telecom operatorsfor long distance calls, is again a simple chaining together of theInternet and PSTN. It may, however, be noted that in this case it isnecessary to provide at least a minimum of feedback to the Internetcalling party on the progress of call set to the destination telephoneover the PSTN local to that telephone; this feedback need only be interms of whether or not the call has succeeded.

From the foregoing it can be seen that the current cooperative use ofthe Internet and telephone system is at a very simple level.

It is an object of the present invention to provide a method ofaccessing a service resource item over a communications network thatfacilitates the integration of the PSTN and the WWW.

SUMMARY OF THE INVENTION

According to the present invention, there is provided a method ofaccessing service resource items for use in respect of setting up bearerchannels through a switched telecommunications system, the methodincluding the steps of:

(a)—provisioning at least one server connected to a computer networkwith a plurality of service resource items that are thereafter locatableon said computer network by corresponding known URIs, said computernetwork being logically distinct from the telecommunications system, andsaid service resource items relating to setup control for bearerchannels through said telecommunications system with each said serviceresource item being associated with a respective predetermined code,said predetermined codes being distinct from said URIs and identifyingend-point entities for said bearer channels;

(b)—providing a mapping between each said predetermined code and thesaid known URI of the service resource item associated with thatpredetermined code; and

(c)—utilising a said predetermined code to access a corresponding saidservice resource item by using said mapping to determine the URIcorresponding to that resource item and then using this URI to accessthe service resource item over said computer network.

In one embodiment, at least some of the URIs are derivable from theircorresponding said predetermined codes by manipulation according to afunction specified by said mapping. In another embodiment, at least someof the URIs are derivable from their corresponding said predeterminedcodes by look up in an association table associating said predeterminedcodes and URIs according to said mapping. This association table canadvantageously be held on at least one database server connected to thecomputer network, step (c) involving accessing the database server overthe computer network to determine the URI corresponding to the saidpredetermined code. Preferably, the said at least one database server isprovided by a DNS-type distributed database system in which the URIs areheld in records associated with respective names, herein referred to asdomain names, by which the records can be retrieved. In this case, step(c) involves translating said predetermined code into a correspondingdomain name and using this domain name to retrieve the URI of therequired service resource item from the DNS-type distributed databasesystem.

More than one service resource item can be located at the same URI; inthis case, the predetermined codes of these service resource items willinclude respective relative-resource-identifier values that can be usedat the server holding the service resource items to identify therequired resource item amongst the service resource items at the sameURI.

The telecommunications system may be a telephone system with each saidpredetermined code being either the telephone number of the callingparty or the telephone number of the called party (these numbers mayeither be the numbers of specific telephones, or personal numbers). Inone preferred embodiment where at least some of said predetermined codesare called-party telephone numbers, the corresponding service resourceitems are the current telephone numbers of the called parties.

Generally as regards the nature of the service resources, these may beof the following type:

service logic intended to be executed by the corresponding server uponbeing accessed with the result of this execution being returned to theaccessing entity;

downloadable service data which upon being accessed is intended to bedownloaded to the accessing entity;

downloadable service logic which upon being accessed is intended to bedownloaded to the accessing entity for execution thereby.

Preferably, where URIs are referred to in the foregoing, these URIs areURLs and/or URNs. Furthermore, the servers referred to are preferablyHTTP servers.

It is to be understood that reference in the foregoing to the computernetwork being logically distinct from the telecommunications system isnot to be taken to imply that there is physical separation of thetwo—indeed, there will frequently be joint use of the same physicalinfrastructure. Furthermore, not only may bearer channels set up in thetelecommunications system share the same transmission medium as thecomputer network, but such a bearer channel may act as a pipe fortraffic across the computer network. The intention of requiring thecomputer network to be logically distinct from the telecommunicationssystem is to exclude computer networks that are dedicated to themanagement or monitoring of the bearer network and effectively form partof the telecommunications system itself.

Preferably, the computer network is generally accessible to users of thetelecommunications system as this provides a number of benefits to usersthat will become apparent hereinafter. The phrase “generally accessible”should not be construed as meaning that all users of thetelecommunications system have such access to the computer network orcan get such access but, rather, it should be understood as meaning thata significant proportion of these users have or can obtain access to thecomputer network.

By way of example, in one preferred embodiment of the invention, thecomputer network generally accessible to users of the telecommunicationssystem but logically distinct from it, is the Internet and thetelecommunications system is a public telephone system. In anotherembodiment, the telecommunication system is a private system including aPABX, and the computer network is a LAN.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will now be described, by way ofnon-limiting example, with reference to the accompanying diagrammaticdrawings, in which:

FIG. 1 is a simplified diagram of a standard PSTN;

FIG. 2 is a simplified diagram of a known PSTN with IN servicecapability;

FIG. 3 is a diagram illustrating host domain name resolution by the DNSof the Internet;

FIG. 4 is a diagram illustrating the functioning of the World Wide Web;

FIG. 5 is a diagram illustrating the format of a standard URL;

FIG. 6 is a diagram of a first arrangement in which service resourceitems are held on HTTP servers accessible both by the service controlsubsystem of a PSTN and by Web users;

FIG. 7 is a diagram illustrating the processing of a service request bythe SCP of FIG. 6;

FIG. 8 is a diagram illustrating the format of a resource code used bythe FIG. 6 SCP when accessing a service resource item;

FIG. 9 is a diagram illustrating the process of accessing a serviceresource in the case where the service code does not include an RRIpart;

FIG. 10 is a diagram illustrating the process of accessing a serviceresource in the case where the service code includes an RRI part;

FIG. 11 is a diagram illustrating the derivation of the URI of a serviceresource by parsing an input telephone number in accordance with thepresent invention;

FIG. 12A is a diagram depicting a name space (the “telname space”)constituted by the domain names derived by a parsing of a predeterminedset of telephone numbers;

FIG. 12B is a diagram depicting the incorporation of the telname spacewithout fragmentation into the DNS;

FIG. 12C is a diagram depicting the incorporation of the telname spacein fragmented form into the DNS;

FIG. 13 is a diagram illustrating the overall operation of the FIG. 6arrangement in providing a roaming number service in response to atelephone number being dialed at a standard phone;

FIG. 14 is a diagram illustrating the overall operation of the FIG. 6arrangement when utilised by a Web user in setting up a call through atelephone interface integrated into the user's Web terminal;

FIG. 15 is a diagram illustrating the overall operation of anarrangement in which an interface is provided between the PSTN and theInternet for telephone traffic;

FIG. 16 is a diagram illustrating the overall operation of anarrangement in which a call setup gateway is provided between theInternet and the PSTN;

FIG. 17 is a diagram illustrating the overall operation of anarrangement in which a freephone service is implemented for Web users;and

FIG. 18 is a diagram similar to FIG. 6 illustrating the provision of adistributed processing environment for interconnecting elements of theservice control subsystem of the PSTN.

BEST MODE OF CARRYING OUT THE INVENTION

FIG. 6 illustrates an arrangement for the provision of services in aPSTN conventionally comprising an inter-exchange network 13 (includingtrunks and switches at least some of which are SSPs 41 with associatedIPs), an access network 11 connecting customer permise equipment (hereshown as telephones 40) to the network 13, and a service controlsubsystem 42 including at least one SCP for providing services to theSSPs 41 upon request. It will be appreciated that the FIG. 6representation of a PSTN is highly diagrammatic.

The SCP 43 may operate in a conventional manner responding to servicerequests from SSPs 41 to run specific service logic on particular dataaccording to information contained in the service request, and to sendback to the requesting SSP appropriate instructions for effecting callset up. A service request is generated by the SSP in response topredetermined trigger conditions being met at a trigger check point,there being one or more such check points in the course of handling acall (it may be noted that where the trigger conditions have beendownloaded to the SSP from the SCP then it could be said that the SSP isresponding to an information request by the SCP when contacting the SCPupon the trigger conditions being met—however, in the presentspecification, this initial communication from the SSP to the SCP willbe referred to as a “service request”).

The SCP 43 is also provided with a network access interface 44 to theInternet 50 in order to make use of certain service resource items 49(also referred to below simply as “service resources”) during the courseof processing at least certain service requests from the SSPs 41. Theseservice resources 49 are held as WWW pages on HTTP servers 51 (moreparticularly, on service resource databases 52 of these servers 51). TheWWW pages containing these service resources are referred to below as“phone” pages. The servers 51 are connected to the Internet and thephone pages are read accessible using respective URLs or URNs (forconvenience, the more general term URI will be used hereinafter to meanthe Internet-resolvable indicator of the location of a phone page).

The service resources may be service logic or service data and may beused by an otherwise standard service logic program running on the SCP,by accessing the phone page of the required resource using theappropriate URI. In certain cases, the service resources 49 may providesubstantially all of the service control and data associated with aparticular service. In this case, the service logic program running inthe SCP 43 is of skeleton form, being instantiated on receipt of aservice request and then serving to initiate service resources accessand to return the results of this access to the entity that made theservice request. In fact, according to this approach, the SCP could beimplemented simply as a platform for fetching and executing phone-pageservice logic and would not need to have the complex provisioning andmanagement systems for such logic as is required by standard SCPplatforms; SCPs could then become more ubiquitous, possibly beingassociated with every SSP.

FIG. 7 is a flow chart illustrating the progress of events in the casewhere the SCP 43 handles a service request by accessing a phone-pageservice resource. Upon receipt of a service request in an INAP message(step 100), SCP 43 decodes the TCAP/INAP message structure in standardmanner (steps 101 and 102) well understood by persons skilled in theart. Next, SCP 43 instantiates a service logic program, SLP, to handlethe request (step 103). This SLP is then responsible for looking up theURL of the required service resource as determined from informationcontained in the service request (steps 104, 105). For example, if theservice request relates to a called-party service, then the requiredresource will be indicated by the dialed number and the latter will beused to derive the URL of the resource. Once the URL of the desiredservice resource has been ascertained, a resource request (for example,in the form of an HTTP request message) is sent over the Internet to thecorresponding server holding the desired service resource (step 106); acorrelation ID is also passed with the resource request to enable aresponse from the latter to be linked with the appropriate SLP instance.A timer is also started (step 107).

If a response is received from the accessed resource before theexpiration of a time-out period (tested in step 108), then the response,which is usually in the form of a destination number, is supplied to theappropriate SLP as identified using the correlation ID passed with theresponse (step 109). An INAP/TCAP response message is then prepared andsent to the entity that made the original service request (steps 110 and111) after which the SLP instance is terminated (113).

If in step 108, a time-out occurs before a response is received, then adefault response value (generally a default destination number) may belooked up in the customer record and put in an INAP/TCAP message andsent back to the requesting entity (steps 114 to 116). The SLP instanceis then terminated (113).

Locating & Accessing Service Resources

The functionality associated with accessing a phone-page resource isschematically represented in FIG. 6 by resource access block 46. Block46 includes URI determination block 47 for determining the URI of thephone page containing the desired resource on the basis of parameterspassed to block 46. Using the URI returned by block 47, the resourceaccess block 46 then accesses the phone page of the required serviceresource 49 over the Internet through interface 44.

Resource Codes—It is possible that more than one service resource isassociated with a particular telephone number; in this case the resourceaccess block 46 will need to know additional information (such ascurrent point-in-call, pic) to enable the appropriate service resourceto be identified. If the service resources associated with a number arelocated on different phone pages, then the additional information isalso passed to the URI determination block 47 to enable it to return theURI of the appropriate phone page. It is also possible for all theservice resources associated with a number to be located on the samephone page. In this case, the resource access block 46 uses theadditional information to pass a resource-identifying parameter with itsaccess request to the phone page concerned; it is then up to thefunctionality associated with the phone page to access the correctservice resource.

Thus, each service resource can be considered as being identified by arespective resource code 54 (see FIG. 8) made up of a first part UI(“URI Identifier”) used to identify the URI at which the resource islocated on the Internet, and a second part RRI (“Relative ResourceIdentifier”) used to identify the resource amongst plural resources atthe same URI.

Resource Access—Where only one service resource 49 is located on a phonepage 58 identified by a unique URI, then the resource code 54 simplycomprises the UI, generally either a telephone number alone or atelephone number plus a pic parameter (see FIG. 9). In this case,accessing a resource simply involves mapping the whole resource code 54into the corresponding URI (process 55) and then sending a request 57 tothe corresponding phone page 58, this latter itself constituting thedesired service resource 49. The result of accessing resource 49 is thenreturned in response message 59.

In contrast, where multiple service resources 49 are located on the samephone page 58 (FIG. 10), the resource code 54 comprises both a UI andRRI, the UI generally being a telephone number and the RRI a pic orother parameter for distinguishing between the co-located resources. Inthis case, accessing a resource involves mapping the UI part of theresource code 54 into the corresponding URI (process 55) and thensending a request 57 to the corresponding phone page (process 56), therequest including the RRI of the resource code. The phone page 58includes functionality 64 for accessing the required resource on thebasis of the RRI in the request message. The result of accessing therequired resource 49 is then returned in response message 59.

An alternative to the FIG. 10 method of accessing a service resourcethat is co-located with other resources on a phone page, would be toretrieve the whole page across the Internet simply using the URI derivedfrom the UI part of the resource code, and then to extract the desiredresource on the basis of the RRI.

URI Determination from Resource Code—The implementation of the URIdetermination block 47 that performs process 55 will next be considered.Block 47 may be implemented in a variety of ways, four of which aredescribed below:

Direct Input

It would be possible, though not necessarily convenient, to arrange forthe calling party to input directly the required URI. The calling partymay thus input the host id component of the URI required (either in theform of a host domain name or host IP address) plus the path componentof the URI. For example, in the case where the phone page of a calledparty is to be accessed, the calling party may input the URI of thecalled party and, indeed, this input may substitute for the normal inputof a telephone number. A leading input string (for example “999”) may beused to identify the input as an URI. As regards the input means, wherea user only has a standard 12 key telephone, input of host domain namesand other URI elements requiring alpha characters, will need to be doneusing one of the standard techniques for alpha input from a phonepad(such techniques are already used, for example, to enable a callingparty to “spell” out the name of the called party). It would also bepossible to provide users with a full alphanumeric keypad to facilitateURI input.

Computation

Service resource access over the Internet could be restricted to a setof dialed numbers from which it was possible to compute a correspondingURI; in this case, this computation would be the responsibility of block47.

Association Table Lookup

Probably the simplest implementation for the block 47 is as anassociation table (either in memory or held on database disc store 48)associating a URI with the UI part of each resource code. A potentialproblem with this approach is that a service resource may be requiredfor a called party number on the other side of the world which implies arigorous update regime between PSTN operators worldwide in order to keepthe association table up-to-date. (Note that the same implication is notnecessarily applicable in respect of marking the called-party number asone required to trigger a service request, since the number may bearranged to be one of a group of numbers all triggering an appropriateservice request, in a manner similar to 800 numbers).

DNS-Type Lookup

An alternative lookup solution is to use a hierarchically-structure-ddistributed database system, similar to (or even part of) the DomainName System (DNS) of the Internet, in order to resolve the UI part of aresource code to a corresponding URI. This approach, which will bedescribed in more detail below, would typically involve databasesmaintained by each PSTN operator for its numbers with which URIs areassociated. These databases would be accessible by all PSTNs through anetwork such as the Internet with resolution requests being pointed tothe appropriate database in a manner similar to the Domain Name System.In this case, the block 47 is constituted by an appropriate resolutionprogram arranged to request UI resolution over the Internet throughinterface 44.

Before describing a DNS-type lookup implementation for the URIdetermination block 47, some further general comments are appropriate.Whatever method is used to determine the URI, certain simplificationsare possible if limited constraints are placed on the URIs permitted. Inparticular, it is not necessary to determine all components of an URI inthe following cases:

(i) A part of the URI path component can be made standard for allservice resources, this standard part being simply added by the block 47once the rest of the URI has been determined. For example, where aroaming number is to be looked up, it may by convention always be heldin a file “roam” in a subdirectory “tel” of a subscriber's directory ona particular server. In this case the URI host component and thesubscriber-unique part of the path component are first determined andthen the remaining path part “/tel/roam” is added.

(ii) The URI path component can be arranged to be the same as apredetermined part of the resource code, the block 47 needing only todetermine the host component and then add the path. For example, it maybe agreed that the path must always end with the telephone numberconcerned, or sufficient of the terminating digits to have a highprobability of uniqueness on the host machine. The path may also includestandard components to be added by block 47.

(iii) Blocks of telephone numbers may have their corresponding serviceresources located on the same host server so that it is only necessaryto use a part of the telephone number to determine the host component ofthe URI; in this case, the path component can conveniently include allor part of each telephone number. This situation implies a tight degreeof control by the telephone operators and does not offer the telephoneuser the freedom to choose the host server on which user places theirphone page.

Another general point worthy of note is that however the URI isdetermined, the host component of the URI may be provided either in theform of a host domain name or a host IP address. Where the host isidentified by a domain name, then a further resolution of URI host nameto IP address will subsequently be carried out in standard manner byinterface 44 using the Domain Name System of the Internet. This furtherresolution can be avoided if the host identity is directly provided asan IP address.

Where a database lookup is used to provide the number to URItranslation, this database may be independent of, or combined with, acustomer database containing other customer-related information. Factorsaffecting this choice include, on the one hand, the possibledesirability of having the number-to-UI translation information widelyavailable, and on the other hand, the possible desirability ofrestricting access to other customer-related information.

DNS-Type URI Lookup

A DNS-type lookup implementation for the URI determination block 47 willnow be described in some detail for the case where the UI part of theresource code is a telephone number and there are no constraints on theURI, thereby requiring both the full host and path components of the URIto be returned by the lookup. A key part of the overall process is theformation of the equivalent of a host domain name from the telephonenumber of interest; this domain-name equivalent is then resolved into acorresponding URI by a lookup mechanism which in the present example isidentical to that employed by the DNS (indeed, the lookup mechanism maybe incorporated into the DNS though it can also be independentlyimplemented).

The nature of the DNS has already been described above with reference toFIG. 3 when the term “DNS-type” system was also introduced. Forconvenience in the following a DNS-type system organised to provide atelephone number to URI translation facility will be referred to as a“Duris” system (standing for “DNS-type URI Server” system).

The basic principles surrounding operation of a Duris system are:

every telephone number can be turned into a host domain name (the namespace containing such host domain names for the telephone numbers ofinterest is referred to below as the “telname space”); and

for every host domain name in the host domain space there is aRegistration Record held by the Duris system containing thecorresponding URI.

Thus, an input telephone number forming, in the present case, the UIpart of a resource code 54 (see FIG. 11), is first parsed to form adomain name (step 120) and then passed to the Duris system (illustratedin FIG. 11 as formed by the DNS itself) to retrieve the RR with thecorresponding URI (step 121). Following on from the URI lookup, if theURI returned has its host component as a domain name, the DNS is nextused to derive the host IP address (step 122); this step is, of coursenot needed if the host component is stored as an IP address in the RR.The URI is then used to make a resource request to the appropriateserver, passing any RRI part of the resource code 54 (step 123).

There are a number of possibilities at the top level as to how a Durissystem could be implemented:

(a) Independent of the DNS. In this option, the telname spaceconstitutes the entire name space to be managed with the root of thetelname space being the “.” name space root (see FIG. 12A where thetelname space is shown hatched). In this case, the Duris system isindependent of the DNS itself. The Duris system could, of course, usethe same basic infrastructure as the DNS (that is, the Internet) or anentirely separate network. Where the telname space comprises all thedomain names corresponding to all public telephone numbers worldwide,parsing a full international telephone number would give a fullyqualified domain name. Of course, the telname space could be a muchsmaller set of names such as those derived from internal extensionnumbers within a company having worldwide operations.

(b) Unfragmented Telname Space within the DNS. In this option, thetelname space is a domain of the DNS name space and the Duris system isprovided by the DNS itself. Thus, where the telname space comprises alldomain names derived from public telephone numbers worldwide, thetelname space could be placed within the domain of the ITU, in a specialsubdomain “tel”, the root of the telname space then being “tel.itu.int.”(see FIG. 12B where again, the hatched area represents the telnamespace). The responsibility for administering the domain “tel.itu.int.”would then lie with the ITU. With this latter example, to form a fullyqualified domain name from an input telephone number, after the numberhas been parsed to form the part of the domain name corresponding to thestructuring within the telname space, the tail “tel.itu.int.” is added.The fully qualified domain name is then applied to the DNS and thecorresponding RR record, holding the required URI, is retrieved. As afurther example, the telname space could be all name derived frominternal extension numbers within Hewlett-Packard in which case the rootof the telname space would be “,tel.hp.com.” and Hewlett-Packard wouldbe entirely responsible for managing this domain.

(c) Fragmented Telname Space within the DNS. In this option, the telnamespace is split between multiple domains of the DNS name space and theDuris system is provided by the DNS itself. Thus where the telname spacecomprises all domain names derived from public telephone numbersworldwide, the telname space could be split between respective “tel”subdomains of each country domain; thus, as illustrated in FIG. 12C, thepart of the telname space corresponding to French telephone numberswould have a root of “tel.fr.” and the part of the telname spacecorresponding to UK telephone numbers would have a root of “tel.uk.”.The responsibility for administering each “tel” subdomain would then liewith each country. With this latter example, to form a fully qualifieddomain name from an input telephone number, the part of the telephonenumber following the country code is parsed to form the part of thedomain name within a country ‘tel’ subdomain and then a host domain nametail is added appropriate for the country concerned. Thus for a Frenchtelephone number, the “33” country code is stripped from the numberprior to parsing and used to add a tail of “tel.fr.”. The tailappropriate to each country can be stored in a local lookup table. As afurther example, two commercial organisations (X company and Y company)with respective DNS domains of “xco.com.” and “yco.com.” may agree tooperate a common Duris system with a telname space split between“tel.xco.com.” and “tel.yco.com”. In this case, any Y company telephonenumber input from X company will be parsed to a fully qualified domainname terminating “tel.yco.com.” and vice versa.

Consideration will next be given to the parsing of a telephone numberinto a domain name—in other words, where to insert the “.” charactersinto the number to provide the structuring of a domain name. Of course,as already explained, telephone numbers are hierarchically structuredaccording to each country's numbering plan. Thus one approach would beto follow this numbering plan structuring in dividing up a telephonenumber to form a domain name. By way of example, the telephone number“441447456987” which is a UK number (country code “44”) with a fourdigit area code (“1447”) and six digit local number (“456987”) could bedivided to form a domain name of 456987.1447.44 (note that the reversalof label order occasioned by the fact that the DNS labels are arrangedleast significant first). If the telname space is a subdomain of the DNSwith a placement as illustrated in FIG. 12B, the fully qualified domainname derived from the telephone number would be:

456987.1447.44.tel.itu.int.

There are however, difficulties inherent with trying to match thenumbering plan hierarchy when parsing a telephone number into a hostname. Firstly, in order to parse an international number correctly, itwould be necessary for each entity tasked with this operation to knowthe structuring of each country's numbering plan and where, as in theUK, area codes may be of differing length the required knowledge mayneed to take the form of a lookup table. Whilst this is not acomplicated computational task, it is a major administrative nuisance asit means that each country will need to inform all others about itsnumbering plan and any updates. The second problem is that a six orseven digit local number is a very large domain; it would be preferableto create subdomains for performance and scaling reasons but there is noobvious way of doing this.

These problems can be overcome by giving up the restriction that theparsing of telephone number into a domain name should match thestructuring of national numbering plans. In fact, there is no strongreason to follow such a scheme as DNS servers know nothing about themeaning of the name space. It is therefore possible to parse telephonenumbers using a deterministic algorithm taking, for example, 4 digits ata time to limit the size of each subdomain and making it possible to‘insert the dots’ without knowing the numbering plan concerned. So longas the DNS domains and zones served by the DNS servers are createdcorrectly it will all work.

For international numbers it would still seem appropriate to separateoff the country codes and so a hybrid parsing scheme would be to parsethe initial part of a dialed number according to known country codes andthereafter use a deterministic scheme (for example 3, 7 or 4, 6 or3,3,4) to separate the digits. Of course, if a fragmented telname spaceis being used as illustrated in Figure UC then the country code is usedto look up the host name tail and it is only the national part of thenumber which would be parsed.

Finally, as regards the details of how a DNS server can be set up tohold RR records with URIs, reference can be made, for example, to “DNSand BIND”, Paul Albitz and Criket Liu, O'Reilly & Associates, 1992 whichdescribes how to set up a DNS server using the Unix BIND implementation.The type of the RR records is, for example, text.

It should be noted that DNS labels should not in theory start with adigit. If this convention is retained, then it is of course a trivialexercise when parsing a telephone number to insert a standard characteras the first character of each label. Thus, a 4 digit label of 2826would become “t2826” where “t” is used as the standard startingcharacter.

It will be appreciated that as with domain names, where an inputtelephone number is not the full number (for example, a local call doesnot require any international or area code prefix), it would be parsedinto a domain name in the local domain.

The foregoing discussion of Duris system implementation, has been interms of translating a telephone number into an URI where the telephonenumber forms the full UI of a resource code and the Duris system returnsa full URI. It will be appreciated that the described Durisimplementation can be readily adapted to accommodate the variousmodification discussed above regarding the form of the UI and what partsof the URI need to be looked up. For example, where there are a numberof differents service resources associated with a subscriber each in itsown file and the required source is identified by a pic part of theresource code, then the input telephone number will be used to look up,not the full URI, but the host component and that part of the pathcomponent up to the relevant subdirectory, the pic part of the UI thenbeing appended to identify the required resource file.

For small local Duris implementations, it may be possible to have asingle server; the implementation should still, however, be consideredas of a DNS type provided the other relevant features are present.

Nature of Service Resources

Turning now to a consideration of the service resources 49, how theseservice resources can be provisioned onto the servers 51 will bedescribed more fully below but, by way of present example, the serviceresource or resources associated with a particular PSTN user (individualor organisation, whether a calling or called party) can be placed on aserver 51 over the Internet from a user terminal 53 in one or more WWWpages.

Consider the simple case where the service resource is a service dataitem such as a telephone number (for example, an alternative number tobe tried if the user's telephone corresponding to the number dialed by acalling party is busy). This diversion number could be made the soleservice resource of a phone page of the user. The phone page URI couldbe a URL with scheme set to HTTP in which case the GET method could beused to retrieve the diversion number. Such an arrangement is suitableif the phone page is only to be used for functional retrieval of thediversion number. However, if the diversion number is to be visuallypresented at a user terminal 53, then it may be desirable to accompanythe number with explanatory material (this will often not be necessaryas the diversion number can be arranged to be returned into an existingdisplayed page that already provides context information). However,where the phone page does include explanatory material as well as thediversion number, an entity only wishing to make functional use of thephone page, could be arranged to retrieve the phone page and thenextract the diversion number (this would, of course, require a standardway of identifying the information to be extracted from the phone page).

An alternative and preferred arrangement for providing for both viewingand functional access to a resource requiring explanatory material forviewing, is to use an object-oriented approach to resource design. Inthis case, the resource object would have two different access methodsassociated with it, one for purely functional use of the resource andthe other enabling viewing of associated explanatory material. It wouldthen be up to the accessing entity to access the resource object usingthe appropriate object method.

Yet another arrangement for providing for both viewing and functionaluse of the diversion number, would be to provide separate resourcesappropriately configured for each use, each resource having its ownresource code (generally, both such resources would be placed on thesame phone page and in this case the UI part of each resource code wouldbe the same).

Retrieval of a phone page for use by a human user will generally not beas time critical as retrieval for operational use by a PSTN. Thus, whilefor human use the scheme specified in the URL of a service resourcecould be HTTP, it may be advantageous for operational use to define aspecial “phone” scheme (access protocol) which would result in theserver 51 using an optimised access routine to access the requiredresource (diversion number, in the current example) and respond to theaccessing entity in the minimum possible time.

Besides data items, other possible types of service resource includeservice logic for execution in place (at the server) with the result ofthis execution being returned to the entity accessing the resource;service logic downloadable from the server to the accessing entity forexecution at that entity; and a logging resource for logging informationpassed to it by the accessing entity (or simply for logging the factthat is has been accessed). It will be appreciated that the loggingresource is really just a particular case of service logic executable inplace.

By way of example, a service resource constituted by execute-in-placeservice logic can be arranged to implement time-of-day routing, theresult of executing the service logic being the telephone number towhich a call should be routed taking account of the time of day at thecalled party's location. An example of a service resource constituted bydownloadable service logic is service logic for controllingcalling-party option interrogation using the facilities provided by anIP. As regards the logging resource, this can be used for recording thenumber of calls placed to a particular number.

Where each resource has its own phone page and the resource is presentonly in its unembellished functional form, then the HTTP scheme can beemployed for access using the GET method for both the downloadableservice logic and the execution-in-place service logic, and the POSTmethod for the logging resource. If it is desired to provide anexplanatory material with each service resource, then any of thesolutions discussed above in relation to data items, can be used.

Where more than one service resource is to be associated with a number,then each such resource can be placed on a respective phone page withits own URI. However, the preferred approach is to place all suchservice resources on the same page and use the RRI part of thecorresponding resource codes to enable access to the appropriateresource. The accessed resource is then treated according to its form(executed if execute-in-place service logic, returned if downloadableservice data or logic).

Thus if both a diversion-number service-data resource and a time-of-dayexecution-in-place service-logic resource are placed on the same phonepage, the diversion-number resource code might have an RRI of “1” whilstthe time-of day resource code might have an RRI value of “2”.

Where calling/called party options are to be included in a serviceresource for presentation to such party, then as already indicated, thiscan conveniently be done by constituting the service resource asdownloadable service logic with the chosen option possibly initiatingrequest for a follow-up service resource.

It will be appreciated that a service resource will often be of acomplex type, combining service data and/or downloadable service logicand/or execute in place service logic. A particularly powerfulcombination is the combination of the two types of service logic wherethe downloadable service logic is designed to interact withexecute-in-place service logic; using this arrangement, the user can bepresented with complex client-server type applications.

Example Usage of Service Resource

FIG. 13 illustrates the operation of a service making use of a resourceon a server 51. This service is equivalent to a “personal number”service by which a user can be accessed through a single, unchangingnumber even when moving between telephones having different realnumbers. To achieve this, the user requiring this service (user B in thecurrent example) is allotted a unique personal number (here referred toas the “Webtel” number of B) from a set of numbers all of which have thesame leading number string to enable an SSP to readily identify a dialednumber as a Webtel number. User B has a service resource 49 on adedicated phone page on HTTP server 51, this phone page being located ata URL here identified as “URL (B phone page)”. B's phone page whenaccessed returns the current roaming number (“B-telNb”) where B can bereached. In the simplest case, B's phone page is just a single numberthat can be modified by B (for example, from a terminal 53) as B movesto a different phone. More likely is that B's phone page is anexecute-in-place service logic providing time of day routing.

In the present example, the association between B's Webtel number andthe URL of B's phone page is stored in an association table accessibleto SCP 43.

Upon a user A seeking to contact user B by dialing the Webtel number ofB, the telephone 40 being used by A passes a call set up request to SSP41 (note that in FIG. 13 the bearer paths through the telephony networkare shown by the thicker lines 60, the other heavy lines indicatingsignaling flows). SSP 41 detects the dialed number as a Webtel numberand sends a service request to SCP 43 together with B's Webtel number.SCP 43 on receiving this service request initiates a service logicprogram for controlling translation of B's Webtel number into a currentroaming number for B; in fact, in the present case, this program simplyrequests the resource access block 46 to access the service resourceidentified by B's Webtel number, (that is, B's phone page 49) and returnthe result of this access. To this end, block 46 first ‘translates B'sWebtel number into the URL of B's phone page and then uses this URL toaccess B's phone page over the Internet (for example, using the ‘phone’scheme already referred to with a method corresponding to the HTTP GETmethod). This results in B's current roaming number B-telNb being passedback to block 46 and in due course this number is returned to the SSP 41which then initiates completion of call set up to the telephone 40corresponding to B-telNb.

The FIG. 13 example related to a called-party service; it will, ofcourse, be appreciated that the principle of accessing service resourcesover the Internet can be applied to all types of services, includingboth calling-party and called-party services and hybrids. Thus, standard800 number services can be implemented with the dialed 800 numberresulting in access to a phone page resource constituted byexecute-in-place service logic that returns the most appropriate numberfor controlling onward call routing.

It will be appreciated that although in the FIG. 13 example the servicerequest from the SSP was triggered by a leading number string of adialed number, a service request may be triggered by a variety oftriggers including calling-party number, called-party number, or someother user input, such triggers being possibly qualified by call setupprogress (for example, called-party number qualified by a busy status orby ringing for more than a certain time).

With respect to the logging service resource mentioned above, onepossible application for such a resource is in telephone voting. In thiscase, dialing the voting number causes the SSP picking up the call topass a service request to SCP 43 which then contacts the appropriatelogging resource over the Internet to register a vote after which thecall is terminated. To minimise bottlenecks, a logging resource could beprovided at a different URL for each SCP, it being a simple matter tocollect and collate voting from all these logging resources over theInternet. If an SCP with Internet access is provided at every SSP, thenthe risk of congestion is greatly reduced.

As already noted, a user's phone page may hold multiple serviceresources in which case the access request from the accessing SCP needsto contain an appropriate RRI identifying the required resource.

In the event that an SCP is to provide both a traditional IN service tosome users and an equivalent service using an Internet-accessed serviceresource to other users, then a lookup table may need to be provided inthe SCP to ensure that a service request is appropriately handled; sucha lookup table can conveniently be combined with the customer recorddatabase.

Once a user, such as user B, has set up one or more phone pagesspecifying his desired service resources (particularly service logicdefining personalised services), it is clearly logical for user B towant any PSTN operator he cares to use, to access and utilise suchservice resources. This is possible if the Webtel-to-URI databases areavailable to all operators. Thus multiple operators could be set toaccess B's phone page or pages. If an operator declines to use B's phonepages, B can obviously chose not to use that operator (at least wherethat operator provides a long haul carrier service subject to userselection). The possibility therefore arises that service provision willcease to command a premium from operators, but that the provision ofphone-page utilisation by an operator will become a necessary basicfeature of PSTN operation.

Provisioning and Updating Service Resources

Consideration will next be given as to how the service resources 49 areprovisioned to the servers 51 and subsequently updated.

So far as provisioning is concerned, two basic actions are required:firstly, the service resource must be placed on a server 51 and,secondly, the URI of the service resource must be notified to the PSTNoperator along with the trigger conditions (number plus any othercondition such as point in call) calling for access to the resource; ifmultiple resources are provided at the same URI, then the RRI valuesneeded to retrieve the appropriate resource for a particular triggercondition, must also be notified. This notification process will bereferred to hereinafter as ‘registering’ the service resource with thePSTN operator; registration is, of course, necessary to enable theassociation tables used by SCP 43 to be set up and for triggerconditions to be set in SSPs 43. For certain services, such as thatdescribed above with reference to FIG. 13, it is not the user thatsupplies the triggering number (the Webtel number in the FIG. 13example); instead, the PSTN operator allocates an appropriate number tothe user as part of the registration process.

As to the process of placing a service resource on a server 51, how thisis carried out will depend on the attitude of the PSTN operator to thepossible effects of such service resources on operation of the PSTN.Where the service resource simply returns a data item to an accessingentity, then an operator may not be too concerned about possible errors(accidental or deliberate) in implementing the service resource.However, the operator will probably be much more concerned about theproper operation of any service logic that may be returned by aresource; indeed, an operator may not permit such a service resource.

Assuming for the moment that an operator has no concerns about thenature or implementation of service resources, then how a resource isplaced on a server 51 will largely depend on the nature of the serverconcerned. For example, if a user has a computer with network access tothe Internet and this computer is used as server 51, then the user cansimply load a desired resource onto the server as a WWW phone page forexternal access. A similar situation arises if the server is anorganisation server to which the server has access over an internal LAN.In both these latter cases, loading the resource as a WWW phone pagedoes not itself require Internet access. However, if the server 51 isone run by an external Internet service provider, then a user canarrange to download the required service resource into the user'sallocated Web site space on the server; this may or may not involveInternet access. One special case of this latter scenario is where thePSTN operator provides a special server for user phone pages containingservice resources.

Except where a user's own computer acts as server 51, placing a serviceresource on a server will generally involve clearing one or more levelsof password protection.

As regards the origin of the service resource loaded by a user ontoserver 51, this may be generated by the user or, particularly where theresource includes service logic, may be provided by a third party(including the PSTN operator).

If the PSTN operator wishes to have control over the service resources49 to avoid any adverse effects on operation of the PSTN, two approachesare possible. Firstly, the operator could require that every resource(or, possibly, a particular subset) had to be subject to a verificationprocess before use, appropriate measures then being taken to avoidsubsequent alteration of the resource by the user (except, possibly, forparticular data items); in this respect, the operator could require thatthe resource be placed on a server under the operator's control and towhich the user had no write access (except possibly for alteringparticular data items, as indicated above). A second, more attractive,approach to minimising adverse effects by the service resources 49, isfor the operator to provide standard service resources to which a usercould-add the user's own data (and possibly make limited functionalselections in case where the resource included service logic); thecustomised resource would then be loaded onto a server 51 controlled bythe operator. This process can be conveniently implemented for aparticular resource using an HTML “form” which a user could downloadover the WWW from the operator-controlled server. After completing theform and activating a ‘commit’ graphical button of the form, the enteredinformation would be ‘posted’ back to the server where the informationwould be used to produce a customised service resource thereafter placedon the server for access over the Internet. An advantage of thisapproach is that registration of the service resource with the operatoris simultaneously effected. (It may be noted that if registration needsto be done as a separate act from having a service resource loaded on aserver, then using an HTML form is a very convenient way to implementthe registration process).

From the foregoing it can be seen that whilst the provisioning processdoes not necessarily require information to be passed over the Internet,in many cases this will be the best solution, particularly if an HTMLform exchanged over the WWW can be used to produce a customised serviceresource. It should be noted that producing a customised serviceresource using an HTML form is not limited to cases where the PSTNoperator controls the server.

As regards updating service resources, there is likely to be a need toupdate certain data items on a fairly frequent basis (for example,roaming number). Where the PSTN operator does not place any controls onthe service resources 49, then update is a relatively simple matter,only requiring write access to the server concerned (as alreadyindicated, this will generally involve one or more levels of passwordprotection). However, where the PSTN operator exercises control over theservice resources, for example by only permitting customisations ofstandard service resources, such customised resources being loaded onservers controlled by the operator), then write access to the serviceresource may be tightly controlled. Again, an HTML form may convenientlybe used as the medium for modifying a data item in such cases; to theoperator, this has the benefit of limiting the modifications possiblewhilst to the user, a form interface should provide a simple route toresource modification.

For more complex updates, it may be necessary to go through a processsimilar to that required for initial provisioning.

Particularly where the service resources are held on a server 51controlled by the PSTN operator, resource update will generally involvecommunication over the Internet.

Web User Interaction

Consideration will next be given to other possible uses of the serviceresources held in phone pages on the servers 51. For example, if userB's phone page contains a diversion number, then provided this phonepage is read-accessible over the Internet from user A's terminal 53,user A can use a graphical Web browser running on terminal 53 to viewB's phone page and discover B's diversion number. As earlier discussed,the diversion number may be passed to user A for display in an existingvisual context giving meaning to the number, or may be passed to user Awith accompanying explanatory text.

A more useful example is a current roaming number service for user B.Suppose B's phone page 49 on server 51 (see FIG. 14) is operative whenaccessed to return a current roaming number where B can be reached.Further suppose that user B has a Web site with several Web pageswritten in HTML and each page contains a graphical ‘phone’ button whichwhen activated uses the GET method to access B's phone page by its URL.Now if user A whilst browsing (arrow 66) B's Web site over the WWW fromuser A's terminal 53, decides that he would like to call user B todiscuss some item of interest, user A simply activates the phone button65 on the currently viewed page of B. This causes B's phone page to beaccessed using the HTTP request “GET URL (B Phone Page)”—see arrow 67.

B's current number to be called is then determined and passed to userA's terminal 53 (see arrow 68) where it is displayed. An explanatorytext concerning the number will generally also be displayed; for examplethe text “Please call me at the following number:” could be displayed,this text being provided either by the HTML script associated with thephone button, or from the phone page when returning the current number.In fact, it would probably be more helpful to provide user A, not onlywith the current number for reaching user B, but also with all numberswhere B could be reached together with the times when B was most likelyto be at each number. Since this extra information is likely to besubject to frequent change, the only sensible way to provide theinformation is from the phone page. Thus, B's phone page not onlyprovides the current number for reaching B, but also a text thatincludes numbers and times subject to change; scripting B's phone pageis, of course, done in a way that ensures that variable data need onlybe altered in one place.

In a further example, B's phone page might include downloadable servicelogic for execution at user A's terminal. This is useful where choicesare to be presented to a user, each choice producing a follow-up actionsuch as fetching a further phone page. For example, the first-accessedphone page may be a family phone page giving the general telephonenumber for a family but also giving the user the possibility ofselecting further phone information on each family member, such as atime-of-day dependent number; in this case, each family member has theirown follow-up phone page.

In the above scenarios, user A has been presented with a number to callover the PSTN. User A can now pick up his standard telephone and dialthe number given. In fact, a complication arises if A only has Internetaccess via a SLIP/PPP connection over an ordinary, non-ISDN, PSTN linesince, in this case, A's telephone line is already tied up with makingInternet access when gateway 90 seeks to set up a call to A's telephone;with an ISDN connection, as two channels are available, this problemdoes not arise. One way of overcoming this problem would be to have userA's terminal 53, after obtaining the number to call from B's phone page,automatically suspend its Internet session by storing any required stateinformation (for example, current WWW URL being accessed) and thenterminate its SLIP/PPP connection to thereby free up the telephone line.A can then telephone B. At the end of this call, A can resume thesuspended Internet session, using the stored state information to returnto the point where A left off to call B. An alternative approach is tooperate a suitable multiplexing modulation scheme on the telephone lineto A allowing voice and data to be simultaneously carried. A number ofsuch schemes already exist. The PSTN would then need to separate thecombined data and voice rams coming from A at some point and pass eachto its appropriate destination (the Internet data being forwarded to theISP providing the SLIP/PPP connection for user A and the voice streambeing passed to B); of course, data and voice traffic in the reversedirection would also need combining at some point for sending over thelast leg to A's terminal.

Rather than A manually dialing B using a standard telephone, anotherpossibility is that user A's terminal is provided with functionalityenabling A to make a call over the PSTN from his terminal; thisfunctionality generally comprises a hardware interface 70 (FIG. 14) to atelephone line and phone driver software 71 for driving the interface 70in response to input from application software such as the Web browser73. A could call up his phone software and enter the required number or,preferably, A need only “select” on screen the number returned from B'sphone page and then pass it into A's phone software. Indeed, provideduser B knew the software interface to the software 71 providing dialingfunctionality on A's terminal, it would be possible for B's phone pageto return to A's terminal program code for automatically dialing B'snumber upon A confirming that he wishes to proceed with call placement.As an alternative to placing a voice call, if A's terminal is equippedwith a suitable modem and controlling software, A could, instead, electto send a fax or data to B through the PSTN either to B's ordinarynumber or to one specified in B's phone page as the number to be usedfor such transmissions. Of course, placing a call from A's terminal overthe PSTN may be subject to the problem already discussed of conflict foruse of the telephone line where this is not an ISDN line and A gainsInternet access via a SLIP/PPP connection.

However the call is placed, if B's telephone corresponding to the numbertried by A is busy, a number of possibilities exist. Thus if B has aphone page that specifies a diversion number, and B has registered thisservice resource with the PSTN, then the diversion number should beautomatically tried by the PSTN. However, if the diversion numberresource has not been registered with the PSTN a busy signal willreturned to A. Where A has placed the call through a standard telephone,A must now decide how to proceed and A may elect either to give up or torefer again to B's phone page to look up the diversion number and redialusing this number. If A placed the original call using his terminal 53then the latter can be programmed to detect the return of a busy signaland then automatically look up B's diversion number and redial usingthis number. This functionality can be included in service logicdownloaded from B's phone page and run on A's terminal.

If A had to terminate his Internet session in order to free up thetelephone line for voice use, then referring back to B's phone pagerequires a new Internet session to be started (in fact, thisinconvenience could be avoided if B's diversion number were passed toA's terminal at the time the original number to be dialed for B wassupplied).

The service resource accessed on B's phone page upon B's telephone beingbusy may, of course, be more complex than just a diversion number. Inparticular, user A may be presented with a range of options including,for example, B's fax or voice mailbox number, the selection of an optionpotentially initiating the running of appropriate accessing software.Another possible option would be for A to leave B a call back messageusing a form downloaded from B's phone page upon this option beingchosen; the completed form would be posted back to server 51 and loggedfor B to check in due course.

Of course, it may arise that user A wishes to access B's phone page tofind out, for example, B's current roaming number, but user A does notknow the URI of B's Web site and only has B's Webtel number. A couldjust call B through the PSTN in which case the translation of B's Webtelnumber to roaming number would be automatically effected (assuming B isstill registered for this service); however, A may not wish to call Bstraight away, but just note his current roaming number. In order tosolve A's problem, the Webtel-to-URI association tables previouslydescribed are preferably made accessible on the Internet at a knownaddress (for example, at a known Web site). All that A need now do is toaccess this Web site passing B's Webtel number; B's phone page URI willthen be returned to A who can then use it to access B's phone page. Thisprocess can, of course be made automatic from the point when A sends B'sWebtel number to the association-table Web site.

Internet/PSTN Call Interface

In the FIG. 14 scenario, A's access to the PSTN was through a standardtelephone interface even though the actual form of A's telephonediffered from standard by being integrated into A's computer terminal53. FIG. 15 illustrates a situation where A, after being supplied withB's current roaming number as in the FIG. 14 case, calls B via a routethat starts out over the Internet and then passes through a user networkinterface 80 into the PSTN. Interface 80 is arranged to convert betweenISDN-type telephone signaling on the PSTN and corresponding signalingindications carried across the Internet in IP packets; in addition,interface 80 transfers voice data from IP packets onto trunk 60 and viceversa.

Thus, upon A initiating a call to B, Internet phone software 81 in A'sterminal sends call initiation signaling over the Internet to interface80, the address of which is already known to A's terminal. At interface80, the signaling is converted into ISDN-type signaling and passed toSSP 41. Call set up then proceeds in the normal way and return signalingis transferred back through interface 80, over the Internet, to thesoftware 81 in A's terminal. This software passes call setup progressinformation to the WWW browser 73 for display to A. Upon the callbecoming established, A can talk to B through his telephone and A'svoice input is first digitised in phone hardware interface 83 and theninserted into IP packets by software 81 to traverse the Internet tointerface 80 (see arrow 84); voice traffic from B follows the reversepath.

IN services can be provided to this call by SCP in response to a servicerequest from an SSP 41. Thus, if B's phone is busy, and B is registeredfor call diversion, SCP 43 on receiving a service request will accessB's appropriate phone page for call diversion and retrieve the diversionnumber. If SSP 41 is not set to initiate a service request on B'stelephone being busy, the busy indication is returned to A's terminalwhere it can be handled in the manner already described with referenceto FIG. 14.

In fact, interface 80 can be provided with functionality similar to anSSP to set trigger conditions and generate a service request to SCP 43on these conditions being satisfied.

Third-Party Call Setup Gateway

FIG. 16 illustrates a further arrangement by which A can call B afterreceiving B's current roaming number. In this case, a third-party callset-up gateway 90 is provided that interfaces both with the Internet 50and with an SSP 41. Conveniently, gateway 90 can be co-located with SCP43 (though this is not essential). Gateway 90 has the capability ofcommanding SSP 41 to set up a call between specified telephones.

Thus, upon A wishing to call B, a third-party call setup request is sentfrom A's terminal over the Internet to the gateway 90 (see arrow 91).This setup request includes A's telephone number and B's current roamingnumber. Gateway 90 first attempts to setup the call to A's telephone(which should generally succeed) and thereafter to set up the call toB's identified telephone. Once the call is setup, A and B communicate instandard manner across the PSTN.

If B's phone had been busy, then any of the previously describedscenarios may ensue.

Gateway 90 can also be arranged to make service requests to SCP 43 uponpredetermined trigger conditions being satisfied. Thus, gateway 90 mightbe set to pick up the busy condition on B's telephone and initiate aservice request to SCP 43 for a diversion number. However passing thebusy indication back to A's terminal via gateway 90 is preferred becauseof the flexibility it gives A regarding further action.

As already generally discussed in relation to FIG. 14, a complicationarises if A only has Internet access via a SLIP/PPP connection over anordinary, non-ISDN, PSTN line since, in this case, A's telephone line isalready tied up with making Internet access when gateway 90 seeks to setup a call to A's telephone. The solutions discussed in respect of FIG.14 (termination of Internet session; multiplexing voice and Internetdata on same telephone line) can also be used here. An alternativeapproach both for FIG. 14 and for FIG. 16 scenarios is possible if userA's terminal can handle a voice call as digitised voice passed over theInternet. In this case, the voice call can be placed through aninterface 80 of the FIG. 15 form, and the voice traffic and the Internetcommunication with the B's phone page and/or gateway 90 are both carriedin Internet packets passed over the SLIP/PPP connection to/from A'sterminal 53 but as logically distinct flows passed to separateapplications ruining on terminal 53.

It may be noted that the third party call setup request made by A'sterminal to gateway 90 could equally have been made by service logicheld in B's phone page and executed by server 51 (such an arrangementwould, of course, require A's telephone number to be passed to B'sphone-page service logic and this could be arranged to occur eitherautomatically or through a form presented to user A at terminal A andthen posted back to server 51).

It may also be noted that the interface 80 of FIG. 15 and the gateway 90of FIG. 516 provide examples of service requests being passed to theservice control subsystem by entities other than SSPs 41.

Www-Based “FreePhone” (800 Number) Services

It is possible to implement a “FreePhone” or “800 number” type ofservice using a combination of the WWW and the PSTN. As will be seenfrom the following description of such a service with reference to FIG.17, a WWW/PSTN implementation does not necessarily rely either ontransferring call charges from the calling to called party or on the useof a special “800” number, two characteristics of standard “Freephone”schemes. The WWW/PSTN implementations do, however, possess the moregeneral characteristic of placing an enquiring party and the party towhom the enquiry is directed, in telephone contact at the expense of thelatter party.

In the FIG. 17 arrangement, a user D such as a large department storehas a website on a server 51; for the sake of simplicity, it will beassumed that the server is under the control of user D who has directcomputer access to the server over line 125. D's Website may, forexample, contain many catalogue-like Web pages illustrating goodsoffered for sale by D. In addition, D has a freephone page 124 forhandling enquiries placed on a freephone basis; the URL of this page isassociated with a “freephone” graphical button 122 placed on each of theWebsite catalogue pages.

Suppose user A at terminal 53 is browsing D's Website, looking at thecatalogue pages (arrow 121). If A sees an item of interest and wishes tomake an enquiry to D about this item, then A can activate at terminal 53the graphical freephone button 122 associated with the catalogue pageconcerned. This activation causes code embedded in the catalogue pagecurrently loaded in A's terminal to prompt the user to enter theirtelephone number and, optionally, their name, after which an HTTPrequest is sent to D's freephone page using the POST method andenclosing the entered data (arrow 123). D's freephone page on receivingthis request executes service logic to enter a new enquiry (includingA's name and telephone number) in an enquiry queue 127 maintained in anenquiry control system 126. In the present example, the enquiry controlsystem is connected to the server 51 via line 125, externally of theInternet; however, it would also be possible to have server 51communicate with the enquiry control system through the Internet and,indeed, this may be the most practical arrangement where D's Website ison an ISP server rather than on a server controlled by D. In fact, thecode run in A's terminal upon activation of the freephone graphicalbutton 122 could be arranged to directly forward the enquiry request tothe enquiry control system over the Internet rather than passing it backthrough the server 51.

The enquiry control system 126 manages enquiries passed to it to ensurethat they are dealt with in an ordered manner. The system 126 onreceiving a new enquiry preferably estimates approximately how long itwill be before the enquiry is dealt with, this estimation being based onthe number of currently queued enquiries and the average time taken tohandle an enquiry. This estimation of waiting time is passed back viaserver 51 to user A in the response to the POST request message.

The enquiry control system 126 looks after the distribution of enquiriesto a number of agents each of which is equipped with a telephone 40 anda display 129. A's enquiry will be dealt with as soon as it reaches thehead of the queue 127 and there is an agent detected as available tohandle the enquiry (thus, for example, the system may be arranged todetect when an agent's telephone goes on hook). When these conditionsare met, a distribution and setup control unit 128 takes A's enquiry anddisplays A's name and telephone number on the display 129 of theavailable agent (for clarity, herein referenced as agent D′); if user Dkeeps a database on D's past customers or credit rating data, then unit128 will also look for and display any such further information knownabout A. At the same time, unit 128 makes a third-party call setuprequest (arrow 130) over the Internet to gateway 90 asking for a call tobe set up between the telephone of the available agent D′ and thetelephone of user A, both telephones being identified by theirrespective numbers. If both D′ and A pick up the call, the enquiry thenproceeds, the cost of the call being paid for by D as it is D thatoriginated the call over the PSTN. If, for whatever reason, the callremains incomplete (for example, unanswered by A) for a predeterminedtimeout period, then unit 128 can be arranged to automatically pass onto the next enquiry at the head of the queue 127.

It would, of course, be possible to dispense with having the unit 128request call setup through gateway 90 and either have the agent D′ dialA's number manually or have unit 126 initiate auto-dialing for D′telephone (agent D′ having, for example, a computer-integrated telephonesimilar to that of A's in FIG. 14). The advantage of these approaches isthat the existing PSTN could be used without adaption and without anyservice installation, in implementing the WWW-based freephone service.

As discussed in relation to FIGS. 11 and 13, a complication arises inplacing a call to A if A only has Internet access via a SLIP/PPPconnection over an ordinary, non-ISDN, PSTN line since, in this case,A's telephone line is already tied up with making Internet access whenuser D tries to set up a call to A's telephone. The solutions discussedin respect of FIGS. 11 and 13 can also be used here (termination ofInternet session; multiplexing voice and Internet data on same telephoneline; and placing the call over the Internet to A's terminal). Withrespect to the solution based on termination of the Internet session,such termination could be delayed until A's enquiry was about to bedealt with; however, to do this, it would be necessary to providefeedback from the control system 126 over the Internet to A's terminal53 and to associate this feedback with code for bringing aboutInternet-session termination. One way to achieve this would be to havethe response message sent by server 51 in reply to the original POSTrequest message from A, include a correlation code; any subsequentfeedback from system 126 passed to A would also include this code(server A having also passed the code to control system 126) therebyallowing A's terminal to correctly identify this feedback. In fact, thesame mechanism could be used to provide user A with updates on how muchlonger user A is likely to be waiting to be called back, this mechanismbeing usable independently of whether or not there was a conflictproblem for use of A's telephone line.

Where user A only has a telephone 40 and no terminal 53, it is stillpossible to utilise the basic structure of FIG. 17 to provide afreephone service for user A without resorting to the complexity of callcharge transfer. More particularly, A would dial a special number foruser D's freephone service (typically an 800 number), and the SSP 41would recognise this special number in standard manner and make aservice request to SCP 43 including both this special number and A'snumber. SCP 43 would then ascertain D's freephone-page URL by doing anumber-to-URL translation and access D's freephone page using aPOST-method HTRP request similar to request 123. Once this request hadbeen registered as an enquiry by D's freephone page 124, the lattercould send a response to SCP 43 asking it to play an announcement suchas “Your freephone enquiry has been registered; please hang up and youwill be contacted shortly”. This announcement could be played to A by anIP in standard manner. A would then hang up and be ready to receive acall from D.

A significant advantage of the above freephone schemes using WWW, isthat user D is not running up charges for use of the PSTN during periodswhen an enquiry is enqueued, waiting to be handled.

Variants

Many variants are, of course, possible to the above-describedarrangements and a number of these variants are described below.

Distributed Processing Environment. As is illustrated in FIG. 18, theSCP 43 may access the HTTP servers 51 through a distributed processingenvironment, DPE 98, at least logically separate from the Internet.Preferably in this case the servers 51 are controlled by PSTN operatorsand are thus restricted in number.

Service Resources on DNS-Type Servers. In the foregoing examples, theservice resource items have been placed on servers 51 connected to theInternet and a desired service resource has then been accessed over theInternet by the service control subsystem of the PSTN, and/or byInternet users, through the use of an URI derived from a resource codethat identifies the desired service resource item. In a preferredarrangement for deriving the URI from a resource code in the form of atelephone number, all or part of the telephone number concerned wasparsed into domain name form and then resolved into an URI using aDNS-type distributed database system that, indeed, could be integratedinto the DNS itself (see FIGS. 11 and 12, and related description). Infact, it would be possible to place service resource items directly inRegistration Records held by a DNS-type distributed database system sothat instead of the parsed telephone number being resolved to an URIwhich is then used to access the required resource, the parsed telephonenumber is directly resolved to the required service resource item. Themechanism employed in this process is exactly as already described forresolving a parsed telephone number into an URI. The DNS-typedistributed database system used for this would preferably be oneaccessible over the Internet or the DNS itself so as to provide accessto the service resource items for Internet users as well as for theservice control subsystem of the PSTN (in the same manner as describedabove with reference to FIG. 18, the DNS-type servers holding theservice resource items may be accessible to the service controlsubsystem by a network other than the Internet). Whilst the placing ofservice resource items in RRs held on DNS-type servers may not besuitable for all types of service resource items, it is suitable foritems such as telephone numbers that do not change frequently. Thus, asuitable usage is to provide number portability; in this case, a dialedpersonal number triggers a lookup in the DNS-type system with all orpart of the personal number being first parsed and then applied to theDNS type system to return a current number for call routing. All dialednumbers could be treated as personal numbers or simply a subset of suchnumbers, this subset comprising numbers that are readily identifiable aspersonal numbers by, for example, local lookup at an SSP or the presenceof a predetermined leading digit string. The general concept of parsinga telephone number (or similar number) in whole or in part to form adomain name for resolution in a DNS-type distributed database system canbe used for the retrieval of other items of information besides URIs andservice resource items.

Feedback Mechanisms. In discussing the WWW-based freephone arrangementof FIG. 17, it was mentioned that user A could be supplied with feedbackon the likely length of waiting time before A would be called back. Thisis one example of using the Internet to provide a feedback path for apotential or actual telephone user. Another example was provided inrelation to FIG. 16 where the progress of call setup was reported backby the call setup gateway to user A's terminal. In fact, generally wherea user is known to be using a terminal actively on the Internet theopportunity arises to provide the user with feedback on the progress ofcall setup through the telephone system. In order to do this, it is ofcourse necessary to ensure that the feedback can be passed to theappropriate application running on terminal A and this will generallyrequire the application to have made appropriate linking informationavailable. As well as call setup progress information, other informationcan also be fedback for example during a call holding period. Thus, forexample, a special server can be provided on the Internet holdingmultimedia clips or even videos that could be output to user A during acall holding period.

In the described arrangements, the servers 51 have held service resourceitems concerned primarily with call setup control. It may be noted thatin a somewhat different application, Internet servers could be arrangedto hold data that could be accessed from the telephone system inresponse to a user-initiated telephone request and returned to thattelephone user. Such a service would he provided, for example, inresponse to an SSP triggering a service request upon a particulartelephone number being input, the service request prompting an SCP tocause an intelligent peripheral to access a particular Internet server(not necessarily an HTTP server) and retrieve the required data forreturn to the calling party. The intelligent peripheral may include atext-to-voice converter for replaying the data vocally to the user.

One further feedback process is also worthy of note, in this case inrelation to service resource items themselves. By way of example, atelephone user G may subscribe to a service by which calls passedthrough to G's telephone are to be separated by a minimum of X minutes,X being user settable. To implement this service, G has a phone page ona server 51 that includes a “busy” status indication. Upon terminationof a successful call to G, G's local SSP triggers the sending of amessage by the associated SCP over the Internet to G's phone page. Thismessage causes G's busy indication to be set to indicate that G is busy;the message also starts a timer which times out after a period X andcauses the busy status indication to be reset. A call attempt to G willeither be rejected at G's SSP because G's line is genuinely busy or willtrigger the SSP to enquire via the SCP whether G's phone-page busystatus indication is set. If the busy status indication is set (which itwill be during the period X following termination of a successful call)the call attempt is rejected whereas if the busy status indication is inits reset condition, the call attempt is allowed to proceed.

By placing the busy status indication mechanism on G's phone page, it ispossible to arrange for G to be able to easily change the value of X.

More General Variants. Whilst the service control subsystem of the PSTNhas been embodied as an SCP in the foregoing examples, it will beappreciated that the functionality of the service control subsystemcould be provided as part of an SSP or in an associated adjunct.Furthermore, the triggering of service requests can be effected byequipment other than SSPs, for example by intercept boxes inserted inthe SS7 signaling links.

It will be appreciated that the term “Internet” is to be understood toinclude not only the current specification of the TCP/IP protocols usedfor the Internet and the current addressing scheme, but also evolutionsof these features such as may be needed to deal with isochronous media.Furthermore, references to the WWW and the HTTP protocol should equallybe understood to encompass their evolved descendants.

The present invention can also be applied to telephone systems otherthan just PSTNs, for example to PLMNs and other mobile networks, and toprivate systems using PABXs. In this latter case, a LAN or campus-widecomputer network serving generally the same internal users as the PABX,will take the role of the Internet in the described embodiments.

Furthermore, the present invention has application where any switchedtelecommunication system (for example, a broadband ATM system) requiresservice control and a computer network can be used for the delivery ofservice resources to the service control subsystem of thetelecommunication system.

1-16. (canceled)
 17. A method, comprising: forming, by a computingsystem, a uniform resource identifier (URI) based on a host componentand a second portion of a resource code, wherein the host component isbased on a first portion of the resource code, and wherein the firstportion of the resource code comprises a numeric string; and retrievinginformation from a service resource associated with the URI.
 18. Themethod of claim 17, wherein the host component is an Internet domainname that includes the numbers of the numeric string.
 19. The method ofclaim 17, wherein the service resource comprises a hypertext markuplanguage (HTML) page stored on a server.
 20. An intransientcomputer-readable medium storing computer-executable instructions forperforming a method, the method comprising: forming a uniform resourceidentifier (URI) based on a host component and a second portion of aresource code, wherein the host component is based on a first portion ofthe resource code, and wherein the first portion of the resource codecomprises a numeric string.
 21. The intransient computer-readable mediumof claim 20, wherein the host component is a host portion of a domainname that includes the numbers of the numeric string.
 22. Theintransient computer-readable medium of claim 20, wherein the URIidentifies a location of a hypertext markup language (HTML) page storedon a server.
 23. The intransient computer-readable medium of claim 20,wherein the resource code comprises a numeric string.
 24. An apparatusfor facilitating accessing a target entity identified at least in partby a number string, in which a domain name system (DNS) of apacket-switched network stores records each associated with acorresponding domain name and holding a URI of an entity associated withthe domain name, each said domain name being related to a respectivenumber string from which it can be derived by a process includingparsing at least a portion of the number string into at least a part ofsaid domain name, said apparatus comprising: a processor; and anintransient computer-readable storage medium storing computer-executableinstructions, which when executed cause the apparatus to: apply saidprocess to said number string identifying the target entity to form therelated domain name, and supply the domain name to the DNS to retrievethe URI held in the corresponding record, the URI being that of thetarget entity.
 25. The apparatus according to claim 24, wherein theapparatus is further configured to use the retrieved URI to access saidtarget entity.
 26. The apparatus according to claim 24, wherein the URIof the target entity comprises an access scheme and host address. 27.The apparatus according to claim 25, wherein the target entity is aninformation entity, the apparatus being further configured to access thetarget entity to retrieve information.
 28. The apparatus according toclaim 25, wherein the target entity is a logging entity, the apparatusbeing further configured to access the target entity to log information.29. An intransient computer readable medium storing computer-executableinstructions for performing a method, the method comprising: forming,from a number string identifying a target entity, a domain name by aprocess including parsing at least a portion of the number string intoat least a part of said domain name; and supplying the domain name to adomain name system of a packet-switched network and receiving back fromthe domain name system a resource record including a uniform resourceidentifier (URI) of the target entity.
 30. The intransient computerreadable medium according to claim 29, wherein the number stringidentifying the target entity is of telephone-number form.
 31. Theintransient computer readable medium according to claim 29, wherein theURI of the target entity comprises an access scheme and host address.32. The intransient computer readable medium according to claim 29,wherein the target entity is an information entity, the method furthercomprising using the URI to access the target entity to retrieveinformation.
 33. The intransient computer readable medium according toclaim 29, wherein the target entity is a logging entity, the methodfurther comprising accessing the target entity to log information. 34.An intransient computer readable medium storing computer-executableinstructions for performing a method, the method comprising: forming,from a number string identifying a target entity, a domain name by aprocess including parsing at least a portion of the number string intoat least a part of said domain name; and supplying the domain name to adatabase and receiving back from that database a resource recordincluding a uniform resource identifier (URI) of the target entity. 35.The intransient computer readable medium according to claim 34, whereinthe said number string identifying the target entity is oftelephone-number form.
 36. The intransient computer readable mediumaccording to claim 34, wherein the URI of the target entity comprises anaccess scheme and host address.
 37. The intransient computer readablemedium according to claim 34, wherein the target entity is aninformation entity, the method further comprising using the URI toaccess the target entity to retrieve information.
 38. The intransientcomputer readable medium according to claim 34, wherein the targetentity is a logging entity, the method further comprising using the URIto access the target entity to log information.
 39. An apparatus,comprising: a network interface; a processor; and a database storing aplurality of resource records that each provides a mapping from a domainname to a uniform resource identifier (URI) for locating a target entityassociated with the domain name, at least a portion of each domain namebeing in the form of a number string that has been parsed into pluraldomain-name labels, wherein the processor is configured to, in responseto an input identifying one of the domain names, output an associatedone of the URIs stored in the database to the network interface.
 40. Theapparatus according to claim 39, wherein the database comprises thedomain name system of the Internet.